X-ray photographing apparatus and method of operating the same

ABSTRACT

An X-ray photographing apparatus and a method of operating the X-ray photographing method are disclosed. The X-ray photographing apparatus includes an X-ray generator configured to generate an X-ray; an X-ray detector configured to detect the X-ray that is transmitted through an object; and a panel that is provided between the X-ray generator and the X-ray detector and configured to contact the object, wherein a distance between a center axis of the X-ray generator and the X-ray detector is maintained to be uniform during a time period, and a radiation angle of the X-ray generated by the X-ray generator with respect to the object changes over the time period.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2013-0073968, filed on Jun. 26, 2013, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

One or more exemplary embodiments relate to an X-ray photographingapparatus using an X-ray and a method of operating the X-rayphotographing apparatus.

2. Description of the Related Art

X-rays are used in non-destructive testing, structural and physicalproperties testing, image diagnosis, security inspection, and the likein the fields of industry, science, medical treatment, etc. Generally,an imaging system using X-rays for such purposes includes an X-raygenerator for radiating an X-ray and an X-ray detector for detectingX-rays that have passed through an object.

The X-ray detector is being rapidly converted from a film device to adigital device, whereas the X-ray generator uses an electron generationdevice having a tungsten filament type cathode. Thus, a single electrongeneration device is mounted in a single X-ray photographing apparatus.The X-ray detector is generally implemented as a flat panel type, whichis problematic in that there is a distance between the X-ray generatorand the object when obtaining an image using the single electrongeneration device. Furthermore, the object needs to be photographed byusing a single X-ray generator, which may make it impossible to selectand photograph a specific part of the object.

SUMMARY

One or more exemplary embodiments provide an X-ray photographingapparatus including a flat panel type X-ray generator and a method ofoperating the X-ray photographing apparatus.

One or more exemplary embodiments further provide an X-ray photographingapparatus capable of obtaining a tomography image and a method ofoperating the X-ray photographing apparatus.

One or more exemplary embodiments further provide an X-ray generatorcapable of adjusting a radiation angle of an X-ray, an X-rayphotographing apparatus including the X-ray generator, and a method ofoperating the X-ray photographing apparatus.

One or more exemplary embodiments further provide an X-ray photographingapparatus for detecting an object and radiating an X-ray only to theobject and a method of operating the X-ray photographing apparatus.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented exemplary embodiments.

According to an aspect of an exemplary embodiment, there is provided anX-ray photographing apparatus including: an X-ray generator configuredto generate an X-ray; an X-ray detector configured to detect the X-raythat is transmitted to an object; and a panel provided between the X-raygenerator and the X-ray detector and configured to contact the object,wherein a distance between a center axis of the X-ray generator and theX-ray detector is maintained to be uniform during a time period, and aradiation angle of the X-ray generated by the X-ray generator withrespect to the object changes over the time period.

The X-ray generator may be configured to radiate the X-ray to the objectin an inclined fashion at a first time and vertically at a second time.

The center axis of the X-ray generator may be configured to move inparallel to the panel over time.

The X-ray generator may be configured to rotate along the center axisthereof and radiate the X-ray to the object in an inclined fashion.

When the X-ray generator radiates the X-ray to the object in an inclinedfashion, the X-ray detector may be disposed to be parallel to the X-raygenerator.

A center axis of the X-ray detector may be configured to move inparallel to the panel over time.

The X-ray generator may include: a plurality of X-ray generation devicesprovided in one dimension; and a rotator configured to support theplurality of X-ray generation devices, wherein the rotator is configuredto rotate over time so that the radiation angle is changed.

The X-ray generator may include: a plurality of electron emissiondevices configured to emit electrons; and an anode electrode configuredto generate the X-ray by using the emitted electrons, wherein theradiation angle differs according to a thickness of the anode electrode.

The anode electrode includes a region having a regular thickness and aregion having an irregular thickness, the X-ray generated in the regionof the anode electrode having the regular thickness may be verticallyradiated to the object, and the X-ray generated in the region of theanode electrode having the irregular thickness is radiated to the objectin an inclined fashion.

A center axis of the X-ray detector and the panel may be configured tomaintain a uniform distance.

The panel may be compressible to the object.

The X-ray photographing apparatus may further include: a gantryincluding the X-ray generator, the X-ray detector, and the panel.

The X-ray generator may be movable in a direction away from or closer tothe object.

The X-ray generator may include a plurality of X-ray generation devicesprovided in two dimensions.

The X-ray photographing apparatus may further include: a processorconfigured to generate a tomography image by using a detection resultobtained by the X-ray detector according to the detected X-ray.

According to another aspect of an exemplary embodiment, there isprovided an X-ray photographing method including: pressing an object byusing a panel; radiating an X-ray to the object at a first radiationangle at a first time by using an X-ray generator; and radiating theX-ray to the object at a second radiation angle different from the firstradiation angle at a second time different from the first time by usingthe X-ray generator, wherein a center axis of the X-ray detector and thepanel maintain a uniform distance during the first time and the secondtime.

The center axis of the X-ray generator may move in parallel to the panelover time between the first time and the second time.

The first radiation angle may be inclined with respect to the object,and the second radiation angle may be vertical with respect to theobject.

The X-ray photographing method may further include: detecting, using theX-ray detector, the X-ray transmitted to the object by radiating theX-ray to the object at the first radiation angle; and detecting, usingthe X-ray detector, the X-ray transmitted to the object by radiating theX-ray to the object at the second radiation angle.

The X-ray photographing method may further include: generating atomography image by using a detection result obtained by the X-raydetector according to the detected X-ray.

According to a aspect of an exemplary embodiment, there is provided anX-ray apparatus including: an electron emission device configured toemit electrons; and an anode electrode configured to emit an X-ray inresponse to the emitted electrons colliding with the anode electrode,wherein the anode electrode comprises a region having an irregularthickness to thereby control a radiation angle of the emitted X-ray.

The region comprises a surface of the anode electrode from which theX-ray is emitted.

The surface decreases in thickness in directions moving away from acenter axis of the anode electrode.

The surface comprises curved surfaces in the directions moving away fromthe center axis of the anode electrode.

The surface comprises planar surfaces in the directions moving away fromthe center axis of the anode electrode.

The surface increases in thickness in directions moving away from acenter axis of the anode electrode.

The surface comprises curved surfaces in the directions moving away fromthe center axis of the anode electrode.

The surface comprises planar surfaces in the directions moving away fromthe center axis of the anode electrode.

The region comprises a surface of the anode electrode from which theX-ray is emitted and another surface opposite the surface.

The region comprises portions of a surface of the anode electrodeprovided between other portions of the surface having a regularthickness.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the exemplary embodiments,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic perspective view of an X-ray photographingapparatus according to an exemplary embodiment;

FIGS. 2A and 2B are schematic diagrams of X-ray generators including aplurality of X-ray generation units according to an exemplaryembodiment;

FIGS. 3A to 3D are schematic diagrams of X-ray generation unitsaccording to exemplary embodiments;

FIG. 4 illustrates an electron emission device including a gateelectrode, according to an exemplary embodiment;

FIGS. 5A to 5G illustrate anode electrodes having irregular thicknesses,according to exemplary embodiments;

FIG. 6 illustrates an anode electrode having a uniform thickness,according to an exemplary embodiment;

FIG. 7 illustrates an anode electrode formed of different materials,according to an exemplary embodiment;

FIGS. 8A and 8B illustrate anode electrodes formed of differentmaterials, according to exemplary embodiments;

FIGS. 9A to 9C illustrate an X-ray generator generating an X-ray of ashort wavelength or an X-ray of a plurality of wavelength bandsaccording to exemplary embodiments;

FIGS. 10A and 10B schematically illustrate X-ray detectors that may beapplied to the X-ray detector of FIG. 1;

FIGS. 11A and 11B are diagrams for explaining an X-ray photographingmethod when an X-ray generation area is smaller than a test area of anobject according to an exemplary embodiment;

FIGS. 12A and 12B are diagrams for explaining an X-ray photographingmethod when an X-ray detection area is smaller than a test area of anobject according to an exemplary embodiment;

FIGS. 13A through 13C are diagrams for explaining an X-ray photographingmethod which may be used to acquire a tomography image according to anexemplary embodiment;

FIGS. 14A through 14C are diagrams for explaining an X-ray photographingmethod which may be used to acquire a tomography image according toanother exemplary embodiment;

FIG. 15 is a schematic diagram of an X-ray generator according to anexemplary embodiment;

FIGS. 16A through 16C are diagrams for explaining an X-ray photographingmethod which may be used to acquire a tomography image according toanother exemplary embodiment;

FIG. 17 is a schematic diagram of an X-ray generator used to acquire atomography image according to an exemplary embodiment;

FIGS. 18A and 18B are schematic diagrams of X-ray generators including aplurality of sensors according to an exemplary embodiment;

FIGS. 19A and 19B illustrate a panel on which sensors are disposedaccording to an exemplary embodiment;

FIG. 20 is a block diagram of an X-ray photographing apparatus accordingto an exemplary embodiment; and

FIG. 21 is a flowchart of an X-ray photographing method according to anexemplary embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present exemplary embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Also, the thickness or size of each element illustrated in the drawingsmay be exaggerated for convenience of explanation and clarity.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.

The attached drawings for illustrating exemplary embodiments arereferred to in order to gain a sufficient understanding of the exemplaryembodiments, the merits thereof, and the objectives accomplished by theimplementation of the exemplary embodiments. The exemplary embodimentsmay, however, be embodied in many different forms and should not beconstrued as being limited to the exemplary embodiments set forthherein; rather, these exemplary embodiments are provided such that thisdisclosure will be thorough and complete, and will fully convey theconcept of the exemplary embodiments to one of ordinary skill in theart.

Hereinafter, the terms used in the specification will be brieflydescribed, and then the exemplary embodiments will be described indetail.

The terms used in this specification are those general terms currentlywidely used in the art in consideration of functions in regard to theexemplary embodiments, but the terms may vary according to the intentionof those of ordinary skill in the art, precedents, or new technology inthe art. Also, specified terms may be selected by the applicant, and inthis case, the detailed meaning thereof will be described in thedetailed description. Thus, the terms used in the specification shouldbe understood not as simple names but based on the meaning of the termsand the overall description of the exemplary embodiments.

In the present specification, an object may include a human being or ananimal, or a part of the human being or the animal. For example, theobject may include organs, such as the liver, the heart, the uterus, thebrain, breasts, the abdomen, or blood vessels. In the presentspecification, a “user” is a medical expert, for example, a doctor, anurse, a medical specialist, and a medical imaging expert, or anengineer managing medical apparatuses; however, the exemplaryembodiments are not limited thereto.

Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

FIG. 1 is a schematic perspective view of an X-ray photographingapparatus 100 according to an exemplary embodiment. The X-rayphotographing apparatus 100 of FIG. 1 is exemplarily shown as amammography apparatus that photographs a breast, but the X-rayphotographing apparatus 100 is not limited thereto. The X-rayphotographing apparatus 100 may be applied to an X-ray photographingapparatus that contacts an object and generates an X-ray.

Referring to FIG. 1, the X-ray photographing apparatus 100 includes anX-ray generator 10 that generates the X-ray, an X-ray detector 20 thatdetects the X-ray that is transmitted to an object 200, and panels 32and 34 that may contact the object 200. The X-ray photographingapparatus 100 may further include a gantry 40 that supports the X-raygenerator 10, the X-ray detector 20, and the panels 32 and 34, and amain body 50 that supports the gantry 40.

The main body 50 may include a user input device 52 that may input auser command to operate the X-ray photographing apparatus 100, aprocessor (not shown) that generates an image corresponding to thetransmitted X-ray, a display 54 that displays the generated image, and acontroller (not shown) that controls general operations of the X-rayphotographing apparatus 100. The user input device 52, the processor(not shown), the display 54, and the controller (not shown) may not benecessarily included in the main body 50, and may instead be implementedas external devices that may communicate with the X-ray photographingapparatus 100 by wire or wirelessly.

The gantry 40 may be fixed to the main body 50 via a gantry driver 42.The gantry 40 may be disposed in one side surface of the main body 50longitudinally. The gantry driver 42 may rotate the gantry 40 by 360° orat an angle. In addition, the gantry driver 42 may operate to move thegantry 40 up and down longitudinally with respect to the main body 50.Thus, the gantry driver 42 may move the gantry 40 up or downlongitudinally with respect to the main body 50 so that a height of thegantry 40 may be adjusted in accordance with the object 200. Further,the gantry driver 42 may rotate the gantry 40.

The panels 32 and 34 that may contact the object 200 may be disposed onthe front of the gantry 40. The first and second panels 32 and 34 maymove up and down by using a guide groove 44 that is longitudinallyincluded in the front of the gantry 40. Thus, if the object 200, forexample, breasts of a patient, is placed between first and second panels32 and 34, at least one of the first and second panels 32 and 34 maypress the object 200 to compress the object 200. For example, the secondpanel 34 may be moved up or down to allow the object 200 to be seated onthe second panel 34 and then the first panel 32 may be moved down topress the object 200 and compress the object 200.

The X-ray generator 10 that generates the X-ray may be disposed on thefirst panel 32. The X-ray generator 10 may be moved far away from orcloser to the object 200 while maintaining a distance d with the firstpanel 32. For example, the X-ray generator 10 may be integrated with thefirst panel 32 so that the X-ray generator 10 and the first panel 32 maymove along the guide groove 44.

In more detail, when the first panel 32 presses the object 200, sincethe X-ray generator 10 radiates the X-ray to the object 200, a distancebetween the X-ray generator 10 and the object 200 may be minimized. Forexample, the distance between the X-ray generator 10 and the object 200may be about 10 cm. Thus, radiation of the X-ray to a region other thanthe object 200 may be prevented, thereby minimizing an X-ray radiationdose. To minimize the distance between the X-ray generator 10 and theobject 200, the X-ray generator 10 may be disposed to contact a top sideof the object 200. The X-ray generator 10 includes a plurality of X-raygeneration units 300, which will be described later.

The X-ray detector 20 that detects the X-ray that is transmitted to theobject 200 may be provided under the second panel 34. The X-ray detector20 may be moved far away from or closer to the object 200 whilemaintaining a distance d with the second panel 34. For example, theX-ray detector 20 may be integrated with the second panel 34 so that theX-ray detector 20 and the second panel 34 may move along the guidegroove 44.

In more detail, when the object 200 is seated on the second panel 34,since the X-ray detector 20 detects the X-ray that is transmitted to theobject 200, a distance between the X-ray detector 20 and the object 200may be minimized. Thus, the X-ray may be more precisely detected. Tominimize the distance between the X-ray detector 20 and the object 200,the X-ray detector 20 may be disposed to contact a bottom side of theobject 200. The X-ray detector 20 includes a plurality of X-raydetection units, which will be described later.

The X-ray generator 10 will now be described in more detail below.

FIGS. 2A and 2B are schematic diagrams of X-ray generators 10 a and 10 bincluding the plurality of X-ray generation units 300 according to anexemplary embodiment. Referring to FIG. 2A, the X-ray generator 10 a mayinclude the X-ray generation units 300 provided in one dimension.Referring to FIG. 2B, the X-ray generator 10 b may include the X-raygeneration units 300 provided in two dimensions.

Each of the X-ray generation units 300 may be independently driven togenerate an X-ray. Accordingly, all of the X-ray generation units 300may be driven to radiate X-rays to the object 200 or, alternatively,some of the X-ray generation units 300 may be driven to radiate X-raysto the object 200. At least one of the X-ray generation units 300 mayradiate X-rays to all regions of the object 200 or a specific region. Inaddition, at least one of the X-ray generation units 300 may besimultaneously or sequentially driven. In this case, only some X-raydetection units corresponding to the X-ray generation units 300 that arebeing driven may be driven.

Although the X-ray generation units 300 are respectively formed on asingle substrate 11 and 12 as shown in FIGS. 2A and 2B, the exemplaryembodiments are not limited thereto. Each of the X-ray generation units300 may be separately manufactured and the X-ray generation units 300may be assembled into the X-ray generators 10 a and 10 b. Alternatively,some of the X-ray generation units 300 may be formed on a singlesubstrate and then assembled together with other X-ray generation units300 formed on other substrates. For example, an X-ray generator in twodimensions may be manufactured by generating X-ray generators in onedimension on a single substrate and providing the X-ray generators inone dimension. Although not shown, an X-ray controller for controlling aproceeding path of an X-ray generated by each of the X-ray generationunits 300 such that the X-ray does not interfere with a neighboringX-ray may be provided. In the X-ray control unit, an opening is formedin an area corresponding to each of the X-ray generation units 300 andan X-ray absorbing material may be formed in a grid type device in theother area (for example, a boundary area between the neighboring X-raygeneration units 300).

FIGS. 3A to 3D are schematic diagrams of X-ray generation units (e.g.,X-ray generation devices) 300 a, 300 b, 300 c, and 300 d according toexemplary embodiments. Referring to FIG. 3A, the X-ray generation unit300 a may include an electron emission device 310 a that may emitelectrons and an anode electrode 320 a that may emit an X-ray bycollision of the emitted electrons. The anode electrode 320 a mayinclude metal or a metal alloy such as W, Mo, Ag, Cr, Fe, Co, Cu, etc.

The electron emission device 310 a may include a cathode electrode 312and an electron emission source 314 that emits electrons and that isprovided on the cathode electrode 312. The cathode electrode 312 may bemetal such as Ti, Pt, Ru, Au, Ag, Mo, Al, W, or Cu, or a metal oxidesuch as indium tin oxide (ITO), aluminum zinc oxide (AZO), indium zincoxide (IZO), tin oxide (SnO₂), or In₂O₃. The electron emission source314 may be formed of a material capable of emitting electrons. Forexample, the electron emission source 314 may be formed of metal,silicon, an oxide, diamond, diamond like carbon (DLC), a carbidecompound, a nitrogen compound, carbon nanotubes, carbon nanofibers, etc.

The cathode electrode 312 applies a voltage to the electron emissionsource 314. When a voltage difference occurs between the electronemission source 314 and the anode electrode 320 a, that is, the cathodeelectrode 312 and the anode electrode 320 a, the electron emissionsource 314 emits electrons and the electrons collide with the anodeelectrode 320 a. Accordingly, the anode electrode 320 a radiates anX-ray due to the collision of electrodes.

As shown in FIG. 3B, an electron emission device 310 b of the X-raygeneration unit 300 b may further include a gate electrode 316 betweenthe electron emission source 314 and the anode electrode 320 a. The gateelectrode 316 may be formed of the same material as the cathodeelectrode 312. The electron emission source 314 may emit electrons basedon the voltage difference between the gate electrode 316 and the cathodeelectrode 312. As the gate electrode 316 is provided between the cathodeelectrode 312 and the anode electrode 320 a, the electrons induced bythe electron emission source 314 based on the voltage applied to thegate electrode 316 may be controlled. Accordingly, the X-ray generationunit 300 b may more stably control the emission of electrons.

In addition, as shown in FIG. 3C, an electron emission device 310 c ofthe X-ray generation unit 300 c may further include a focusing electrode318 provided between the electron emission source 314 and an anodeelectrode 320 b. The focusing electrode 318 may be formed of the samematerial as the cathode electrode 312. The focusing electrode 318focuses the electrons emitted from the electron emission source 314 onan area of the anode electrode 320 b so as to collide the electronstherewith. A voltage applied to the focusing electrode 318 may be thesame as or similar to the voltage applied to the gate electrode 316 sothat an optimal focusing performance may be maintained.

As shown in FIG. 3D, an electron emission device 310 d of the X-raygeneration unit 300 d may include the cathode electrode 312, theelectron emission source 314 that emits electrons and that is providedon the cathode electrode 312, the gate electrode 316 spaced apart fromthe cathode electrode 312, and the focusing electrode 318 which focusesthe emitted electrons.

FIG. 4 illustrates an electron emission device 400 including a gateelectrode 420, according to an exemplary embodiment.

Referring to FIG. 4, the electron emission device 400 may include acathode electrode 410, the gate electrode 420 having a mesh structurespaced apart from the cathode electrode 410, a plurality of insulationlayers 430 and a plurality of electron emission sources 440 that extendin a first direction between the cathode electrode 410 and the gateelectrode 420 and are spaced apart from each other. A substrate 450 forsupporting the electron emission device 400 may be formed of aninsulation material such as glass. The substrate 450 may support asingle electron emission device 400 or the electron emission sources440.

The cathode electrode 410 and the gate electrode 420 may be formed of aconductive material. The cathode electrode 410 may apply a voltage toeach of the electron emission sources 440 and may have a flat panelshape. When the cathode electrode 410 has a flat panel shape, thesubstrate 450 may not be necessary. The gate electrode 420 may have amesh structure including a plurality of openings H. For example, thegate electrode 420 may include a plurality of gate lines 422 separatedfrom each other and provided on the insulation layers 430, and mayfurther include a plurality of gate bridges 424 connecting the gatelines 422. Accordingly, the two neighboring gate lines 422 and the twoneighboring gate bridges 424 form the openings H.

The openings H may be provided to expose at least a part of the electronemission sources 440 between the insulation layers 430. As describedabove, since the gate electrode 420 has a mesh structure, a largeelectron emission device 400 may be manufactured. Although the openingsH of the gate electrode 420 are each shown as being rectangular in FIG.4, the exemplary embodiments are not limited thereto. Shapes of theopenings H may be various other types of shapes, such as at least one ofcircles, ovals, and polygons. The sizes of the openings H may beidentical or different from each other.

The insulation layers 430 are provided between the cathode electrode 410and the gate electrode 420 and prevent electrical connection between thecathode electrode 410 and the gate electrode 420. The insulation layers430 are provided in multiple numbers and at least three insulationlayers 430 may be provided. The insulation layers 430 may have a linearshape. The insulation layers 430 extend in one direction and areseparate from one another and support the gate electrode 420. Theinsulation layers 430 may each include a first insulation layer 432supporting an edge area of the gate electrode 420 and a secondinsulation layer 434 supporting a middle area of the gate electrode 420.

The insulation layers 430 may be formed of an insulation material usedfor a semiconductor device. For example, the insulation layers 430 maybe formed of HfO₂, Al₂O₃, or Si₃N₄, which is a high-K material having ahigher dielectric rate than SiO₂ or SiO₂, or a mixture thereof.

Although the insulation layers 430 are shown as having a linear shape inFIG. 4, the exemplary embodiments are not limited thereto. Theinsulation layers 430 may have a different shape that prevents anelectrical connection between the cathode electrode 410 and the gateelectrode 420 and supports the gate electrode 420. For example, thesecond insulation layer 434 may have a column shape and may be providedunder the gate lines 422.

The electron emission sources 440 emit electrons due to the voltageapplied to the cathode electrode 410 and the gate electrode 420. Theelectron emission device 400 of FIG. 4 may include the electron emissionsources 440. The electron emission sources 440 may be alternatelyprovided with the insulation layers 430. For example, the electronemission sources 440 may be spaced apart from one another with thesecond insulation layer 434 interposed between the neighboring electronemission sources 440. The electron emission sources 440 may be shaped asstrips extending in the first direction, similar to the secondinsulation layer 434.

Since the gate electrode 420 has a mesh structure, the gate electrode420 is provided above the electron emission sources 440. The electronemission sources 440 may be spaced apart from the gate electrode 420 toprevent the electron emission sources 440 and the gate electrode 420from being short-circuited.

The electron emission sources 440 may be formed of a material capable ofemitting electrons. As an area occupied by the electron emission sources440 in the electron emission device 400 increases, the electron emissiondevice 400 may emit a large amount of electrons. However, the electronemission device 400 may endure an electrostatic force due to adifference in the voltages applied between the electron emission sources440 and the gate electrode 420. Accordingly, the insulation layers 430and the electron emission sources 440 are alternately provided, and thegate electrode 420 having the openings H is provided over an area whereeach of the electron emission sources 440 is provided, therebyimplementing the large area electron emission device 400.

Since the gate electrode 420 includes the gate bridges 424 provided in adirection crossing the lengthwise direction of the electron emissionsources 440, a uniform electric field may be formed on surfaces of theelectron emission sources 440.

Although the electron emission sources 440 are shown as being formed instrips in FIG. 4, the exemplary embodiments are not limited thereto. Theelectron emission sources 440 may be formed as a point type in an areacorresponding to the openings H above the cathode electrode 410. Thepoint-type electron emission sources 440 may be provided in a twodimensional array, that is, in a matrix format.

Although the electron emission sources 440 are shown as being providedin the single electron emission device 400 in FIG. 4, the exemplaryembodiments are not limited thereto. Also, only one electron emissionsource may be provided in the electron emission device 400 or two ormore electron emission sources may be provided therein.

A proceeding path of the X-ray may be controlled by the shape of ananode electrode. In detail, as the thickness of the anode electrode isprovided to be irregular, the proceeding path of the X-ray radiated fromthe anode electrode may be controlled.

FIGS. 5A to 5G illustrate anode electrodes having irregular thicknessesaccording to exemplary embodiments. The anode electrode illustrated ineach of FIGS. 5A to 5G corresponds to a single X-ray generator. However,the exemplary embodiments are not limited thereto. One anode electrodemay correspond to one electron emission device. For convenience ofexplanation, one anode electrode corresponding to a single X-raygenerator will be described below.

As shown in FIGS. 5A to 5G, the anode electrode may be symmetricallyprovided about a center axis X of the X-ray generator 10 so that anX-ray may be symmetrically radiated.

The thicknesses of anode electrodes 510 and 520 gradually decrease fromthe center axis X of the X-ray generator 10 toward edges thereof, asillustrated in FIGS. 5A and 5B. When the thicknesses of the anodeelectrodes 510 and 520 gradually decrease from the center axis X of theX-ray generator 10 toward edges thereof, X-rays radiated from the anodeelectrodes 510 and 520 may propagate to be focused at the center axis Xof the X-ray generator 10. Thus, the X-ray generator 10 may efficientlyradiate an X-ray in a partial area of the object.

In more detail, surfaces 512 and 522 of the anode electrodes 510 and520, on which electrons are incident, may be flat surfaces, whereassurfaces 514 and 524 from which X-rays are emitted may be convexsurfaces. The surfaces 514 and 524 from which X-rays are emitted may beconvexly curved surfaces or convex surfaces obtained by combining flatsurfaces. A position where the X-ray is focused may be determined bylevels, θ and R, of the convex shape. Although FIGS. 5A and 5Billustrate that the surfaces 512 and 522 of the anode electrodes 510 and520 on which electrons are incident are flat and the surfaces 514 and524 from which X-rays are emitted are convex, the exemplary embodimentsare not limited thereto. That is, the surfaces on which electrons areincident may be convex, whereas the surfaces from which X-rays areemitted may be flat.

The thicknesses of anode electrodes 530 and 540 gradually increase fromthe center axis X of the X-ray generator 10 toward edges thereof, asillustrated in FIGS. 5C and 5D. When the thicknesses of the anodeelectrodes 530 and 540 increase from the center axis X of the X-raygenerator 10 toward edges thereof, the X-rays radiated from each of theanode electrodes 530 and 540 may propagate toward an area larger than asectional area of each of the anode electrodes 530 and 540. Thus, theX-ray generator 10 may radiate an X-ray to a relatively large area of anobject.

In more detail, surfaces 532 and 542 of the anode electrode 530 and 540,on which electrons are incident, may be flat surfaces, whereas surfaces534 and 544 from which X-rays are emitted may be concave surfaces. Thesurfaces 534 and 544 from which X-rays are emitted may be concavelycurved surfaces or concave surfaces obtained by combining flat surfaces.A size of an area where the X-ray is radiated may be determined bylevels, θ and R, of the concave shape. Although FIGS. 5C and 5Dillustrate that the surfaces 532 and 542 of the anode electrodes 530 and540 on which electrons are incident are flat and the surfaces 534 and544 from which X-rays are emitted are concave, the exemplary embodimentsare not limited thereto. That is, the surfaces on which electrons areincident may be concave, whereas the surfaces from which X-rays areemitted may be flat.

In addition, as shown in FIG. 5E, both surfaces of an anode electrode550, including a surface on which electrons are incident and a surfacefrom which X-rays are emitted, may be convex. In this case, a focaldistance of an X-ray may become shorter. Additionally, both surfaces onwhich electrons are incident and from which X-rays are emitted may beconcave. Alternatively, while one of the surfaces on which electrons areincident and from which X-rays are emitted may be concave, the othersurface may be convex.

The thickness of an anode electrode may be partially irregular. Forexample, as illustrated in FIGS. 5F and 5G, anode electrodes 560 and 570may have a shape in which only some parts are convex. A convex shape 566may be identical to others or a convex shape 576 may be different fromothers according to an area. Nevertheless, the thicknesses of the anodeelectrodes 560 and 570 may be symmetrical with respect to the centeraxis X of the X-ray generator 10. Although FIGS. 5F and 5G illustrateonly a convex shape, the exemplary embodiments are not limited thereto.The anode electrode may have a concave shape or both a concave shape anda convex shape.

As such, since the propagating path of an X-ray may be controlled byusing the anode electrode having an irregular thickness, the X-raygenerator 10 may not only efficiently radiate an X-ray to the object butmay also reduce an unnecessary X-ray radiation dose.

The X-ray photographing apparatus 100 according to an exemplaryembodiment may use an anode electrode having a uniform thickness. FIG. 6illustrates an anode electrode 580 having a uniform thickness, accordingto an exemplary embodiment. Referring to FIG. 6, while the anodeelectrode 580 having a uniform thickness is used, the propagating pathof an X-ray may be controlled by using a separate constituent elementsuch as a collimator (not shown).

In addition, the anode electrode may include a plurality of layersformed of different materials and capable of radiating X-rays ofdifferent wavelengths. FIG. 7 illustrates an anode electrode 710 formedof different materials, according to an exemplary embodiment. As shownin FIG. 7, the anode electrode 710 may include a plurality of layers711, 712, 713, and 714 formed of different materials. The layers 711,712, 713, and 714 may be provided in a parallel fashion with respect toan electron emission device. The anode electrode 710 may radiate X-raysof different wavelengths according to the layers 711, 712, 713, and 714with which electrons collide.

An anode electrode radiating X-rays of multiple wavelengths may not havea uniform thickness as described above. FIGS. 8A and 8B illustrate anodeelectrodes 810 and 820 formed of different materials, according toexemplary embodiments. Each of the anode electrodes 810 and 820 mayinclude a plurality of layers formed of different materials and at leastone of the layers may have an irregular thickness.

For example, as shown in FIG. 8A, the anode electrode 810 may include aplurality of layers 811, 812, 813, and 814 that are formed of differentmaterials. The layers 811, 812, 813, and 814 have thicknesses thatgradually decrease from the center axis X of the X-ray generator 10toward edges thereof. Accordingly, the anode electrode 810 may focus theradiated X-rays. Since the X-rays having different wavelengths arefocused on different areas, a single linear X-ray generator mayphotograph many different areas at different depths of the object at onetime.

In addition, as shown in FIG. 8B, the anode electrode 820 may include aplurality of layers 821, 822, and 823 that are formed of differentmaterials. The anode electrode 820 may have a change in the thicknessthereof according to the layers 821, 822, and 823. For example, thefirst layer 821 may have a thickness that gradually decreases from thecenter axis X of the X-ray generator 10 toward an edge thereof, thesecond layer 822 may have a uniform thickness, and the third layer 823may have a thickness that gradually increases from the center axis X ofthe X-ray generator 10 toward the edge thereof. Accordingly, the anodeelectrode 820 may radiate an X-ray to a larger surrounding area whilefocusing on an area of interest of the object.

The X-ray generator 10 according to the present exemplary embodiment maysimultaneously or selectively generate X-rays of different wavelengths.FIGS. 9A to 9C illustrate an X-ray generator generating an X-ray of ashort wavelength or simultaneously generating X-rays of a plurality ofwavelength bands, according to exemplary embodiments.

Referring to FIG. 9A, a plurality of electron emission devices 910, eachhaving an electron emission source 912, are provided and an anodeelectrode 920 may be provided separately from the electron emissiondevices 910. In the anode electrode 920, first and second layers 922 and924 that are formed of different materials may be alternately provided.When the first and second layers 922 and 924 overlap with each other inan area corresponding to the electron emission source 912 of one of theelectron emission devices 910, electrons emitted by the electronemission devices 910 may collide with the first and second layers 922and 924. Accordingly, the anode electrode 920 may simultaneously radiatea first X-ray X1 and a second X-ray X2.

As shown in FIG. 9B, the anode electrode 920 makes a translationalmovement in parallel with the electron emission devices 910 such thatthe first layer 922 of the anode electrode 920 may be arranged tooverlap with the electron emission source 912. Then, the electronsemitted by the electron emission devices 910 collide with the firstlayer 922, and thus the first X-ray X1 may be radiated from the anodeelectrode 920.

As shown in FIG. 9C, the anode electrode 920 makes a translationalmovement in parallel with the electron emission devices 910 such thatthe second layer 924 of the anode electrode 920 may be arranged tooverlap with the electron emission source 912. Then, the electronsemitted by the electron emission devices 910 collide with the secondlayer 924, and thus the second X-ray X2 may be radiated from the anodeelectrode 920.

As such, since the anode electrode 920 simultaneously radiates aplurality of X-rays or selectively radiates a single X-ray, usability ofthe X-ray generator 10 may be improved.

As described above, X-ray generation units are provided in an X-raygenerator 10. Each of the X-ray generation units is separatelymanufactured as one unit and then the X-ray generation units areassembled, thereby forming the X-ray generator 10. A plurality ofelectron emission devices and an anode electrode may be integrallymanufactured on a single substrate. Alternatively, a plurality ofelectron emission devices may be manufactured on a single substrate andthen an anode electrode may be assembled, thereby forming a linear X-raygenerator. In addition, the linear X-ray generator may be formed by avariety of different methods.

Additionally, the X-ray generator may further include a collimator (notshown) for controlling a proceeding direction of an X-ray. Accordingly,an unnecessary X-ray radiation dose may be reduced, and an X-ray may bealso more accurately detected.

FIGS. 10A and 10B schematically illustrate X-ray detectors 1000 a and1000 b that may be used as the X-ray detector 20 of FIG. 1. As shown inFIG. 10A, the X-ray detector 1000 a may be configured as a plurality ofX-ray detection units 1010 provided in one dimension. Alternatively, asshown in FIG. 10B, the X-ray detector 1000 b may be configured as theplurality of X-ray detection units 1010 provided in two dimensions.

Each of the X-ray detection units 1010 is a light-receiving element thatreceives an X-ray and converts a received X-ray into an electric signal,and may include, for example, a scintillator 1011, a photodiode 1012,and a storage element 1013. The scintillator 1011 receives an X-ray andoutputs photons, in particular visible photons, that is, a visible ray,according to a received X-ray. The photodiode 1012 receives the photonsoutput from the scintillator 1011 and converts the received photons intoelectric signals. The storage element 1013 is electrically connected tothe photodiode 1012 and stores the electric signal output from thephotodiode 1012. In this regard, the storage element 1013 may be, forexample, a storage capacitor. The electric signal stored in the storageelement 1013 of each of the X-ray detection units 1010 is transmitted toa processor (not shown) where the signal is processed into an X-rayimage.

The X-ray detectors 1000 a and 1000 b may detect an X-ray by using aphotoconductor configured to directly convert an X-ray into an electricsignal.

The X-ray detection units 1010 may be provided to correspond to theX-ray generation units 300 of an X-ray generator. The X-ray generationunits 300 and the X-ray detection units 1010 may have a one-to-onecorrespondence. Alternatively, each of the X-ray generation units 300may correspond to two or more X-ray detection units 1010, or two or moreX-ray generation units 300 may correspond to one X-ray detection unit1010.

The X-ray detection units 1010 may be simultaneously or independentlydriven to detect an X-ray. Accordingly, an X-ray passing through theentire area of the object may be detected as all of the X-ray detectionunits 1010 are driven, or an X-ray passing through a particular area ofthe object may be detected as some of the X-ray detection units 1010 aredriven. Also, at least one of the X-ray detection units 1010 may besimultaneously or sequentially driven.

Although the X-ray detection units 1010 are shown as being formed on asingle substrate, the exemplary embodiments are not limited thereto.Each of the X-ray detection units 1010 may be separately manufactured,and the X-ray detection units 1010 may be assembled into the X-raydetectors 1000 a and 1000 b. Alternatively, some of the X-ray detectionunits 1010 may be formed on a single substrate and then assembledtogether with the other X-ray detection units 1010 formed on othersubstrates. For example, X-ray detectors in one dimension may beprovided on a single substrate and then arranged, and thus, X-raydetectors in two dimensions may be manufactured.

When an X-ray generation area of the X-ray generator and X-ray detectionareas of the X-ray detectors 1000 a and 1000 b are equal to or largerthan a test area of the object, the linear X-ray generator and the X-raydetectors 1000 a and 1000 b may photograph the object by performing oneoperation. The X-ray photographing apparatus 100 may photograph thewhole object at one time or a partial area of the object. When a partialarea of the object is to be photographed, only some of the X-raygeneration units 300 of the X-ray generator may operate to generate anX-ray, and only some of the X-ray detection units 1010 corresponding tothe operating X-ray generation units 300 may be synchronized to detectthe X-ray.

However, when at least one of the X-ray generation area of the X-raygenerator and the X-ray detection areas of the X-ray detectors 1000 aand 1000 b is smaller than the test area of the object, at least one ofthe X-ray generator and the X-ray detectors 1000 a and 1000 b may bemoved and driven two times or more.

FIGS. 11A and 11B are diagrams for explaining an X-ray photographingmethod when an X-ray generation area A is smaller than a test area B ofthe object 200 according to an exemplary embodiment. When the X-raygeneration area A of an X-ray generator 1110 is smaller than the testarea B, the X-ray generator 1110 may move along a first panel 1132 togenerate an X-ray, thereby generating the X-ray in the entire test areaB of the object 200.

For example, referring to FIG. 11A, the X-ray generator 1110 radiates anX-ray to a first area B1 of the object 200. Then, a first detector 1122of an X-ray detector 1120 detects an X-ray that was transmitted to thefirst area B1. Referring to FIG. 11B, the X-ray generator 1110horizontally moves along the first panel 1132 and then radiates an X-rayto a second area B2 of the object 200. In this regard, the second areaB2 and the first area B1 may not overlap with each other. Thus, an X-rayradiation dose of the object 200 may be minimized. A second detector1124 of the X-ray detector 1120 corresponding to the second area B2detects an X-ray of the second area B2. Although the X-ray generationarea A of the X-ray generator 1110 is ½ the test area B in FIGS. 11A and11B, the exemplary embodiments are not limited thereto. The X-raygeneration area A may be 1/n (where n is a natural number equal to orgreater than 2) the test area B.

FIGS. 12A and 12B are diagrams for explaining an X-ray photographingmethod when an X-ray detection area C is smaller than the test area B ofan object according to an exemplary embodiment. When the X-ray detectionarea C of the X-ray detector 1120 is smaller than the test area B, theX-ray detector 1120 may move along a second panel 1234 to detect anX-ray, thereby detecting the X-ray that is transmitted to the entiretest area B of the object 200.

For example, referring to FIG. 12A, a first X-ray generator 1212 of anX-ray generator 1210 generates X-rays to be transmitted to the firstarea B1 of the object 200. Then, an X-ray detector 1220 detects an X-rayof the first area B1. Referring to FIG. 12B, the X-ray detector 1220horizontally moves along the second panel 1234. Then, a second X-raygenerator 1214 of the X-ray generator 1210 generates X-rays to betransmitted to the second area B2 of the object 200. The X-ray detector1220 detects an X-ray of the second area B2. In this regard, the secondarea B2 and the first area B1 may not overlap with each other. Thus, anX-ray radiation dose of the object 200 may be minimized. Although theX-ray detection area C of the X-ray detector 1120 is ½ the test area Bin FIGS. 12A and 12B, the exemplary embodiments are not limited thereto.The X-ray detection area C may be 1/n (where n is a natural number equalto or greater than 2) the test area B.

In addition, when the X-ray generation area A and the X-ray detectionarea C are smaller than the test area B and correspond to each otherone-to-one, the X-ray generators 1110 and 1210 and the X-ray detectors1120 and 1220 may be synchronized to photograph a partial region of thetest area B. Each of the X-ray generators 1110 and 1210 and the X-raydetectors 1120 and 1220 may horizontally move along the first and secondpanels 1132 and 1234 and photograph other regions of the test area B.

When the X-ray generation area A and the X-ray detection area C aresmaller than the test area B, and the X-ray generation area A is smallerthan the X-ray detection area C, the X-ray photographing method of FIGS.12A and 12B may be applied to photograph a partial region of the testarea B. Each of the X-ray generators 1110 and 1210 and the X-raydetectors 1120 and 1220 may horizontally move along the first and secondpanels 1132 and 1234 and photograph other regions of the test area B.Furthermore, when the X-ray generation area A and the X-ray detectionarea C are smaller than the test area B, and the X-ray detection area Cis smaller than the X-ray generation area A, the X-ray photographingmethod of FIGS. 12A and 12B may be applied to photograph a partialregion of the test area B. Each of the X-ray generators 1110 and 1210and the X-ray detectors 1120 and 1220 may horizontally move along thefirst and second panels 1132 and 1234 and photograph other regions ofthe test area B.

The X-ray photographing apparatus 100 according to an exemplaryembodiment may acquire a tomography image of the object 200. To acquirethe tomography image, the X-ray generators may radiate an X-ray to theobject by varying a radiation angle to the object. The X-ray generatorsaccording to an exemplary embodiment may vary the radiation angle to theobject by horizontally moving with respect to the object. In thisregard, horizontal moving refers to horizontal moving of center axes ofthe X-ray generators.

To acquire the tomography image, the X-ray generators may radiate anX-ray to the object at multiple locations. When the X-ray is radiated atmultiple locations, the center axes of the X-ray generators may move inparallel to the object. Furthermore, the X-ray generators may radiate anX-ray by varying a radiation angle according to locations thereof. Forexample, the X-ray generators may radiate an X-ray to the objectvertically at a first location and in an inclined fashion at a secondlocation. In this regard, the X-ray detectors may be disposed under theobject. The X-ray detectors may be fixed, although are not limitedthereto.

FIGS. 13A through 13C are diagrams for explaining an X-ray photographingmethod which may be used to acquire a tomography image according to anexemplary embodiment. Referring to FIG. 13A, when an X-ray generator1310 is disposed on a left upper portion of the object 200, the X-raygenerator 1310 may rotate with respect to a center axis P1 thereof suchthat an X-ray radiation direction is changed from the left upper portionto a right lower portion. The X-ray generator 1310 radiates an X-ray ata first radiation angle 83 toward the object 200, and thus, an X-rayphotographing apparatus may photograph a first image of the object 200.

The X-ray generator 1310 may move to the right. When the X-ray generator1310 moves, the center axis P1 of the X-ray generator 1310 may move inparallel to the object 200. When the X-ray generator 1310 is disposed onthe object 200, the X-ray generator 1310 may adjust its posture to allowan X-ray to face the object 200. For example, the X-ray generator 1310may rotate in a clockwise direction with respect to the center axis P1of the X-ray generator 1310, and thus, as shown in FIG. 13B, the X-raygenerator 1310 may be disposed in parallel to the object 200. The X-raygenerator 1310 may vertically radiate an X-ray to the object 200. TheX-ray photographing apparatus may photograph a second image of theobject 200.

The X-ray generator 1310 may move in parallel to the right until theX-ray generator 1310 is disposed on a right upper portion of the object200. When the X-ray generator 1310 is disposed on the right upperportion of the object 200, the X-ray generator 1310 may adjust itsposture to allow an X-ray generated by the X-ray generator 1310 to beradiated in an inclined fashion to the object 200. For example, as shownin FIG. 13C, the X-ray generator 1310 may rotate in a clockwisedirection with respect to the center axis P1 of the X-ray generator1310. The X-ray generator 1310 may radiate an X-ray at a secondradiation angle θ4 toward the object 200, and thus, the X-rayphotographing apparatus may photograph a third image of the object 200.

When the X-ray generator 1310 moves in a horizontal direction withrespect to an X-ray detector 1320, the X-ray generator 1310 rotates withrespect to the center axis P1 thereof according to a location. An orderof horizontal movement and rotational movement may be switched, and thesecond image of the object 200 may be photographed in advance and thefirst image or the third image may be photographed.

The X-ray detector 1320 may detect an X-ray by moving to correspond to aposition of the X-ray generator 1310. FIGS. 14A through 14C are diagramsfor explaining an X-ray photographing method which may be used toacquire a tomography image according to another exemplary embodiment.

Referring to FIG. 14A, when the X-ray generator 1310 is disposed on aleft upper portion of the object 200, the X-ray generator 1310 mayrotate with respect to the center axis P1 thereof such that an X-ray maybe radiated in an inclined fashion to the object 200. In this regard,the X-ray detector 1320 may also move to face the X-ray generator 1310.For example, the X-ray detector 1320 may move to be disposed on a rightlower portion of the object 200 and rotate with respect to a center axisP2 of the X-ray detector 1320 such that the X-ray generator 1310 and theX-ray detector 1320 may be disposed in parallel to each other. The X-raygenerator 1310 may radiate an X-ray at a first radiation angle 83 to theobject 200, and thus, an X-ray photographing apparatus may photograph afirst image of the object 200.

Referring to FIG. 14B, the X-ray generator 1310 may move to be disposedon the object 200. Furthermore, the X-ray generator 1310 may adjust itsposture such that the X-ray generator 1310 may be disposed in parallelto the object 200. In this regard, the X-ray detector 1320 may alsomove. For example, the X-ray detector 1320 may move to be disposed underthe object 200 and rotate with respect to the center axis P2 thereofsuch that the X-ray generator 1310, the object 200, and the X-raydetector 1320 may be disposed in parallel to each other. The X-raygenerator 1310 may vertically radiate an X-ray to the object 200, andthus, the X-ray photographing apparatus may acquire a second image ofthe object 200.

Referring to FIG. 14C, the X-ray generator 1310 may move to a rightupper portion of the object 200 and adjust its posture such that anX-ray is radiated in an inclined fashion to the object 200. In thisregard, the X-ray detector 1320 may also move to be disposed in parallelto the X-ray generator 1310. For example, the X-ray detector 1320 maymove to be disposed on a left lower portion of the object 200 and rotatewith respect to the center axis P2 thereof such that the X-ray generator1310, the object, 200, and the X-ray detector 1320 may be disposed inparallel to each other. The X-ray generator 1310 may radiate an X-ray ata second radiation angle θ4 to the object 200, and thus, the X-rayphotographing apparatus may acquire a third image of the object 200.

As described above, the X-ray generator 1310 may move to vary aradiation angle of an X-ray and radiate the X-ray to the object 200,thereby simplifying a photographing process for acquiring a tomographyimage.

Furthermore, the X-ray generator 1310 and the X-ray detector 1320 mayrotate, and thus, photographing may be performed to acquire thetomography image.

FIG. 15 is a schematic diagram of an X-ray generator 1510 according toan exemplary embodiment. Referring to FIG. 15, the X-ray generator 1510according to an exemplary embodiment may include a plurality of X-raygeneration units 1511 provided in one dimension and a rotation unit(e.g., rotator) 1513 that supports and rotates the X-ray generationunits 1511. The X-ray generator 1510 may include a driver (not shown)that drives the rotation unit 1513. If the rotation unit 1513 rotates ata predetermined time interval, the X-ray generation units 1511 disposedon the rotation unit 1513 may radiate an X-ray to an object at differentradiation angles at the predetermined time interval. An X-ray detectormay include a rotation unit, similar to the X-ray generator 1510.

FIGS. 16A through 16C are diagrams for explaining an X-ray photographingmethod so as to acquire a tomography image according to anotherexemplary embodiment.

Referring to FIG. 16A, a rotation unit 1613 may rotate such that eachX-ray generation unit 1613 of an X-ray generator 1610 may radiate anX-ray to the object 200 at the first radiation angle 83 at a first time.For example, the rotation unit 1613 may rotate in a counterclockwisedirection at the first time. The X-ray generator 1610 may radiate theX-ray to the object 200 at the first radiation angle 83, and thus, anX-ray photographing apparatus may acquire a first image of the object200.

Referring to FIG. 16B, each X-ray generation unit 1611 rotates in aclockwise direction at a second time after a predetermined time elapsesand then the X-ray generator 1610 may vertically radiate an X-ray to theobject 200. The X-ray photographing apparatus may acquire a second imageof the object 200. Furthermore, referring to FIG. 16C, each of the X-raygeneration units 1611 rotates in a clockwise direction at a third timeafter a predetermined time elapses and then the X-ray generator 1610 mayvertically radiate an X-ray to the object 200 at the second radiationangle θ4. The X-ray photographing apparatus may acquire a third image ofthe object 200. In this regard, X-ray detection units 1621 may rotatesimilar to the X-ray generation units 1611 to detect an X-ray.

As described above, an X-ray radiation angle may be changed by rotatingonly the X-ray generation units 1611, thereby simplifying aphotographing process for acquiring the tomography image.

Furthermore, a shape of an anode electrode among the X-ray generationunits 1611 may be used to change the X-ray radiation angle with respectto the object 200. FIG. 17 is a schematic diagram of an X-ray generator1710 used to acquire a tomography image according to an exemplaryembodiment. Referring to FIG. 17, the X-ray generator 1710 may includean anode electrode 1712 that emits an X-ray due to collisions between aplurality of electron emission devices 1711 that are independentlydriven and electrons. The anode electrode 1712 may have a differentthickness with respect to a center axis P3 of the X-ray generator 1710.For example, if the anode electrode 1712 is divided into three regions,a thickness of the first region 1712 a increases in a direction movingfrom an edge towards the center axis P3 of the X-ray generator 1710, athickness of a second region 1712 b is uniform, and a thickness of athird region 1712 c decreases in a direction moving away from the centeraxis P3 of the X-ray generator 1710 towards an edge. Thus, an X-ray fromthe first region 1712 a is radiated to the object 200 at the firstradiation angle 83, an X-ray from the second region 1712 b may bevertically radiated to the object 200, and an X-ray from the thirdregion 1712 c may be radiated to the object 200 at the second radiationangle θ4.

If the electron emission device 1711 corresponding to the first region1712 a emits electrons at a first time, the X-ray generated in the firstregion 1712 a may be radiated to the object 200 at the first radiationangle 83. If the electron emission device 1711 corresponding to thesecond region 1712 b emits electrons at a second time, the X-raygenerated in the second region 1712 b may be vertically radiated to theobject 200. If the electron emission device 1711 corresponding to thethird region 1712 c emits electrons at a third time, the X-ray may begenerated in the third region 1712 c. The X-ray generated in the thirdregion 1712 c may be radiated to the object 200 at the second radiationangle θ4. Thus, an X-ray photographing apparatus may perform X-rayphotographing to acquire the tomography image by using a shape of theanode electrode 1712.

The X-ray photographing to acquire the tomography image may be performedthree times, according to an exemplary embodiment. However, this exampleis simply for convenience of description, and X-ray photographing may beperformed two or more times to acquire the tomography image according toother exemplary embodiments.

The X-ray photographing apparatus according to the present exemplaryembodiment may further include a sensing unit that senses the object200. The sensing unit may include a plurality of sensors. Each sensormay sense an existence of the object 200 and determine a location of theobject 200 based on results of sensing by all the sensors. The sensorsmay be light sensors (in particular, illumination sensors), touchsensors, etc. In particular, when the sensors are touch sensors, thesensors may be formed as a single pad, e.g., a touch pad.

FIGS. 18A and 18B are schematic diagrams of X-ray generators 1810 a and1810 b including a plurality of sensors 1871 according to an exemplaryembodiment. The sensors 1871 may be provided to be integrated with theX-ray generators 1810 a and 1810 b. Referring to FIG. 18A, a onedimensional sensor array 1870 is provided at a side of the onedimensional X-ray generator 1810 a so that the one dimensional X-raygenerator 1810 a and the one dimensional sensor array 1870 may beintegrated. Alternatively, referring to FIG. 18B, the sensors 1871 maybe provided to be spaced apart from each other on a two dimensionalX-ray generator 1810 b. The sensors 1871 may be disposed not to overlapwith X-ray generation units 1811. In FIG. 18B, the sensors 1871 aredisposed on regions in which four X-ray generation units 1811 areadjacent. In particular, the sensors 1871 may be disposed on the sameplane of the X-ray generators 1810 a and 1810 b as an anode electrode(not shown). Thus, an X-ray traveling path may not be influenced by thesensors 1871. However, the exemplary embodiments are not limitedthereto. Locations of the sensors 1871 may be varied in many differentways, as long as the X-ray traveling path and the sensors 1871 do notoverlap with each other.

Although the sensors 1871 are exemplarily shown as being disposed on theentire regions in which the X-ray generators 1810 a and 1810 b aredisposed, the exemplary embodiments are not limited thereto. When a sizeand location of an object are generally known, the sensors 1871 may notbe provided in a region in which the object is necessarily disposed orin a region in which there is no possibility that the object is to bedisposed. The sensors 1871 may be focused in a region corresponding to aboundary of the object. The sensors 1871 provided on the X-raygenerators 1810 a and 1810 b may be light sensors.

Although the sensors 1871 are exemplarily shown as being integrallyformed with the X-ray generators 1810 a and 1810 b in FIGS. 18A and 18B,the exemplary embodiments are not limited thereto. The sensors 1871 maybe integrally formed with X-ray detectors. For example, when X-raydetectors are one dimensional X-ray detectors, the sensors 1871 may bedisposed to contact the X-ray detectors. When the X-ray detectors aretwo dimensional X-ray detectors, the sensors 1871 may be disposedbetween the X-ray detectors.

FIGS. 19A and 19B illustrate a panel 1932 on which sensors 1971 aredisposed according to an exemplary embodiment. Referring to FIG. 19A,the sensors 1971 may be disposed on the panel 1932. If the sensors 1971are disposed on an X-ray generator, when the X-ray generator does notcover an object, the X-ray generator should be moved in a horizontaldirection to detect a location of the object. However, since the panel1932 covers the object, when the sensors 1971 are disposed on the panel1932, the object may be more easily detected. The sensors 1971 may bedisposed on a surface of the panel 1932 facing the X-ray generator or ona surface of the panel 1932 facing the object. The sensors 1971 disposedon the panel 1932 may be light sensors, touch sensors, etc. When thesensors 1971 are disposed on the panel 1932, the sensors 1971 may beformed of a transparent material so as to minimize diffusion of an X-rayor absorption by the sensors 1971. In particular, when the sensors 1971are touch sensors, the sensors 1971 may be implemented as a touch pad1980.

FIG. 20 is a block diagram of the X-ray photographing apparatus 100 ofFIG. 1 according to an exemplary embodiment. Referring to FIG. 20, theX-ray photographing apparatus 100 may include an X-ray generator 10, anX-ray detector 20, the user input device 52, a display 54, a processor56, and a controller 60. The X-ray photographing apparatus 100 mayfurther include a sensing unit 70 that senses an object.

The X-ray generator 10 radiates an appropriate X-ray to the object asdescribed above. Since the X-ray generator 10 has been described above,a description thereof will not be repeated here. The X-ray detector 20detects the X-ray that is transmitted to the object. Since the processof the X-ray detector 20 detecting the X-ray has been described above, adescription thereof will not be repeated here.

The user input device 52 receives input of an X-ray photographingcommand from a user such as a medical expert. Information regarding acommand to change a location of the X-ray generator 10, a parameteradjustment command to vary an X-ray spectrum, a command regarding a mainbody of the X-ray photographing apparatus 100 or a movement of the X-raygenerator 10, and many other types of commands received from the user,may be transmitted to the controller 60. The controller 60 controlselements included in the X-ray photographing apparatus 100 according toa user command.

The processor 56 receives an electrical signal corresponding to theX-ray detected by the X-ray detector 20. The processor 56 may preprocessthe electrical signal to acquire an image. In this regard, preprocessingmay include at least one of offset compensation, algebra conversion,X-ray dose compensation, sensitivity compensation, and beam hardening.The image may be a tomography image.

The processor 56 may preprocess the electrical signal corresponding tothe detected X-ray to acquire the image. The processor 56 may preprocessan electrical signal corresponding to the detected X-ray to acquiretransparent data and reconfigure the acquired transparent data for eachradiation angle to acquire the tomography image.

Configurations, locations and types of the sensing unit 70 have beendescribed above, and thus a detailed description thereof will not berepeated here. Each sensor included in the sensing unit 70 may sense anexistence of the object and transmit a result of the sensing to thecontroller 60. Thus, the controller 60 may determine a location of theobject by using results of the sensing by the sensors. The controller 60may control the X-ray generator 10 to enable an X-ray generation unit ofthe X-ray generator 10 corresponding to the location of the object togenerate an X-ray. Furthermore, the controller 60 may control the X-raydetector 20 to enable an X-ray detection unit of the X-ray detector 20corresponding to the location of the object to detect an X-ray that istransmitted to the object.

According to an exemplary embodiment, only some of the X-ray generationunits operate to photograph the object, thereby reducing an X-rayradiation dose. Furthermore, only some of the X-ray detection unitsoperate, and thus, a lifetime of the X-ray detector 20 may be increased,thereby simplifying signal processing.

An X-ray photographing method using the sensing unit 70 will now bedescribed. FIG. 21 is a flowchart of an X-ray photographing methodaccording to an exemplary embodiment. Referring to FIG. 21, the sensingunit 70 senses the object 200 at operation S2110. If the object 200 isdisposed between the first panel 32 and the second panel 34 of the X-rayphotographing apparatus 100 of FIG. 1, the X-ray photographing apparatus100 may move at least one of the first panel 32 and the second panel 34according to a user command to compress the object 200. If the object200 contacts the first panel 32 and the second panel 34 or is pressed bythe first panel 32 and the second panel 34, each sensor included in thesensing unit 70 may sense an existence of the object 200. For example,when sensors are illumination sensors, the sensors may sense whether theobject 200 exists based on an illumination change, and when the sensorsare touch sensors, the sensors may sense whether the object 200 existsaccording to whether the touch sensors are touched. A result of thesensing by each sensor is transmitted to the controller 60.

The controller 60 may control the X-ray generator 10 to enable an X-raygeneration unit of the X-ray generator 10 corresponding to a location ofthe object 200 to generate an X-ray by using results of the sensing bythe sensing unit 70 at operation S2120. The controller 60 may determinethe location of the object 200 from the result of the sensing by eachsensor. For example, the location of the object 200 may be determinedfrom locations of the sensors that detect the illumination change andwhether the sensors are touched. The location of the object 200 may bedetermined to be slightly greater than locations of the sensors. Thecontroller 60 may control the X-ray generation unit of the X-raygenerator 10 corresponding to the location of the object 200 to generatethe X-ray. An X-ray generation method may vary according to sizes of anX-ray test area and an X-ray generation area, and according to whetheran image that is to be photographed is a simple image or a tomographyimage. Since these features have been described above, a detaileddescription thereof will not be repeated here.

The controller 60 may control the X-ray detector 20 to enable an X-raydetection unit of the X-ray detector 20 corresponding to the location ofthe object to detect the X-ray at operation S2130. An X-ray detectionmethod may vary according to sizes of the X-ray test area and the X-raygeneration area, and according to whether the image that is to bephotographed is the simple image or the tomography image. Since thesefeatures have been described above, a detailed description thereof willnot be repeated here. If only the X-ray detection unit of the X-raydetector 20 corresponding to the location of the object detects theX-ray, the X-ray diffused by being transmitted to the object 200 isdetected, thereby blocking noise.

Then, the processor 56 may receive an electrical signal corresponding tothe X-ray detected by the X-ray detection unit to acquire an image atoperation S2140. The acquired image may be displayed on the display 54.

Although the above description exemplarily describes that the sensingunit 70 senses the object 200, and the X-ray photographing apparatus 100operates according to a result of the sensing, the exemplary embodimentsare not limited thereto. For example, when the sensing unit 70 is notincluded in the X-ray photographing apparatus 100, the X-rayphotographing apparatus 100 may perform photographing as described withreference to FIGS. 11A through 16C.

It should be understood that the exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exemplaryembodiment should typically be considered as available for other similarfeatures or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described withreference to the figures, it will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the exemplaryembodiments as defined by the following claims.

What is claimed is:
 1. An X-ray photographing apparatus comprising: anX-ray generator configured to generate an X-ray; an X-ray detectorconfigured to detect the X-ray that is transmitted through an object;and a panel that is provided between the X-ray generator and the X-raydetector and configured to contact the object, wherein a radiation angleof the X-ray generated by the X-ray generator with respect to the objectis configured to change with a distance between a center axis of theX-ray generator and a center axis of the X-ray detector maintained to beconstant, and the X-ray generator comprises: a plurality of electronemission devices configured to emit electrons; and an anode electrodeconfigured to generate the X-ray by using the emitted electrons, whereinthe radiation angle differs according to a thickness of the anodeelectrode.
 2. The X-ray photographing apparatus of claim 1, wherein theX-ray generator is configured to radiate the X-ray to the object in aninclined fashion at a first time and vertically at a second time.
 3. TheX-ray photographing apparatus of claim 1, wherein the center axis of theX-ray generator is configured to move in parallel to the panel overtime.
 4. The X-ray photographing apparatus of claim 1, wherein the X-raygenerator is configured to rotate along the center axis thereof andradiate the X-ray to the object in an inclined fashion.
 5. The X-rayphotographing apparatus of claim 1, wherein, when the X-ray generatorradiates the X-ray to the object in an inclined fashion, the X-raydetector is disposed to be parallel to the X-ray generator.
 6. The X-rayphotographing apparatus of claim 1, wherein a center axis of the X-raydetector is configured to move in parallel to the panel over time. 7.The X-ray photographing apparatus of claim 1, wherein the X-raygenerator comprises: a plurality of X-ray generation devices provided inone dimension; and a rotator configured to support the plurality ofX-ray generation devices, wherein the rotator is configured to rotateover time so that the radiation angle is changed.
 8. The X-rayphotographing apparatus of claim 1, wherein the anode electrodecomprises a region having a regular thickness and a region having anirregular thickness, the X-ray generated in the region of the anodeelectrode having the regular thickness is vertically radiated to theobject, and the X-ray generated in the region of the anode electrodehaving the irregular thickness is radiated to the object in an inclinedfashion.
 9. The X-ray photographing apparatus of claim 1, wherein acenter axis of the X-ray detector and the panel is configured tomaintain a uniform distance.
 10. The X-ray photographing apparatus ofclaim 1, wherein the panel is compressible to the object.
 11. The X-rayphotographing apparatus of claim 1, further comprising a gantrycomprising the X-ray generator, the X-ray detector, and the panel. 12.The X-ray photographing apparatus of claim 1, wherein the X-raygenerator is movable in a direction away from or closer to the object.13. The X-ray photographing apparatus of claim 1, wherein the X-raygenerator comprises a plurality of X-ray generation devices provided intwo dimensions.
 14. The X-ray photographing apparatus of claim 1,further comprising a processor configured to generate a tomography imageby using a detection result obtained by the X-ray detector according tothe detected X-ray.